Dishwasher pump assembly



Feb. 4, 1969 F. E.ILA FLAME ET AL 3,425,355

DISHWASHER PUMP. ASSEMBLY Filed July 14, 1967 Sheet of 4 (1 l6 fly. Z w

2 @(OQ MG) ZWEZZ iZ QZZ;

I omzrzzfmrdma w t g AITORNE Y Feb. 4, 1969 F. E. LA FLAME ET AL DISHWASHER PUMP ASSEMBLY IN VEN TORS 25222145 fizf/mze 6 She e t 615/2261? Z/Macfidzzza ATTO p NFY Filed July 14, 1967 4, 1969 F. E. LA FLAME mm 3,425,355

DISHWASHER PUMP ASSEMBLY Filed July 14, 1967 Sheet 3 0f 4 ATTORNEY Feb. 4, 1969 F. E. LA FLAME ET AL DISHWASHER PUMP ASSEMBLY Sheet Q of Filed July 14, 1967 INVENTORS I fiam Z ZZfl /ame (5 monf/fila aw/ma 5 M ATTORNEY United States Patent 3,425,355 DISHWASHER PUMP ASSEMBLY Frank E. La Flame, Dayton, and Gordon F. MacFarland,

Kettering, Ohio, assiguors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed July 14, 1967, Ser. No. 653,413 U.S. Cl. 103-3 Int. Cl. F04b 19/04; F04d 13/02; B08b 3/04 4 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a dishwasher apparatus including an improved pumping assembly for circulating fluid in a cleaning chamber during a washing cycle of operation and draining fluid therefrom during a drain cycle of operation.

To obtain desirable article cleaning action in domestic dishwashing apparatus, recent practice includes a plural pump assembly in a lower sump region of the apparatus operated by a reversible, electrically energized drive motor located exteriorly of the sump region having a vertically oriented drive shaft secured to a drain impeller and a wash impeller located respectively in a drain pumping chamber and a wash pumping chamber each having inlets and outlets, the inlets being in fluid communication with the sump region of the dishwasher apparatus, the outlet of the wash pump adapted to be connected to suitable fluid distributing means such as a water reaction spray arm or the like and the drain pump outlet adapted to be connected through suitable drain conduit means to a waste drain located exteriorly of the dishwashing apparatus, for example, a typical household drain system. Energization of the drive motor of such units is programmed to produce reverse motor rotation to produce separate and distinct wash and drain phases of operation during the complete cleaning cycle of dishwasher operation.

By virtue of the inclusion of plural pumps in the assembly, several important considerations must be taken down into account to adapt such an assembly for use in dishwashing apparatus. One important consideration is the outer dimensional configuration of the assembly. To maintain the maximum use of a dishwasher cleaning chamber volume for washing articles on racks or the like, the outer configuration of the assembly should be as compact as possible.

Another important consideration is that the component parts of the assembly should be easily and quickly mass produced and assembled both with respect to the sump of the dishwasher, with respect to the drive motor for the assembly and with respect to one another without concern for tolerance differences between the component parts.

An additionally important consideration in present day dishwashing apparatus is the inclusion of features in such plural pump assemblies that eliminate the need for scraping dishes prior to stacking them in the dishwasher. The features typically in the past have been directed to various proposals for straining fluid prior to passage thereof from the sump into the pump assembly. To supplement the straining action, in many of the plural pump assemblies, a wash pump impeller configuration is present that is capable of reducing the size of certain soft food particles during the Patented Feb. 4, 1969 washing cycle of operation thereby to prevent sludge accumulation in the sump region sufiicient to block passage of fluid into the drain pump inlet during the drain phase of dishwasher operation.

An object of the present invention is to improve dishwashing apparatus by the provision therein of a plural pump assembly including a plurality of molded plastic components easily interconnected and configured to eliminate tolerance dilferences between the component parts whereby the pump assembly can be quickly assembled with respect to a sump forming member of a dishwasher and a drive motor in a mass production operation.

A further object of the present invention is to improve dishwashing apparatus by the provision therein of a motor driven, plural pump fluid circulating assembly including a wash pump having a turbo impeller with a depending skirt thereon forming an inlet throat to the impeller and wherein the depending skirt sealingly engages an annular sealing member having its outer periphery supported for free radial movement on an interiorly located support flange of the pump housing to prevent fluid by-passing between a high pressure pumping chamber and a low pressure inlet chamber within the pump housing and wherein with the inlet throat defined by the depending skirt is located an axial impeller component that during a washing cycle of machine operation is operative to emulsify soft food particles while shielding angular pumping vanes on the turbo impeller of the wash pump from hard food particles and wherein during a drain cycle of operation the axial impeller is operative to produce a pressure differential across the inlet throat region causing fluid to be drawn from the pump spaces within the turbo impeller to remove fluid from the high pressure wash pumping chamber during the drain cycle of dishwasher operation thereby to reduce noise emanating from the pumping assembly during the drain cycle of operation and to concurrently reduce the operating load on the pump assembly.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein preferred embodiments of the present invention are clearly shown.

In the drawings:

FIGURE 1 is a fragmentary elevational view of a domestic dishwasher apparatus partially broken and partially sectioned and including the present invention;

FIGURE 2 is an enlarged, fragmentary, vertical sectional view of a motor driven, plural dishwasher pump assembly of the present invention;

FIGURE 3 is an exploded perspective view showing component parts of the plural dishwasher pump assemy;

FIGURE 4 is a horizontal sectional view taken along the line 4-4 of FIGURE 2 looking in the direction of the arrows;

FIGURE 5 is a horizontal sectional view taken along the line 55 of FIGURE 2 looking in the direction of the arrows;

FIGURE 6 is a fragmentary horizontal sectional view taken along the line 66 of FIGURE 2 looking in the direction of the arrows;

FIGURE 7 is an enlarged vertical sectional view of the wash impeller of the present invention;

FIGURE 8 is a bottom elevational view of the wash impeller of FIGURE 7;

FIGURE 9 is an enlarged top elevational view of an axial impeller in the present invention;

FIGURE 10 is a vertical sectional view taken along the line 1010 of FIGURE 9 looking in the direction of the arrows;

FIGURE 11 is a detailed view showing the vane contour in FIGURES 9 and 10;

FIGURE 12 is an enlarged vertical sectional view of the hub of another wash impeller embodiment taken along line 12--12 of FIGURE 13;

FIGURE 13 is a top elevational view of the hub in FIGURE 12;

FIGURE 14 is a top elevational view of another wash impeller embodiment;

FIGURE 15 is a vertical sectional view of the wash impeller of FIGURE 14; and

FIGURE 16 is a fragmentary vertical view taken along line 1616 of FIGURE 15.

Referring now to the drawings, in FIGURE 1, a domestic dishwasher apparatus 10 is illustrated including an outer casing 12 defining a dishwashing chamber 14 having a bottom bulkhead 16 that forms a downwardly inclined lower sump region 18 in the chamber 14. The downwardly depending segment of the bottom bulkhead 16 forming the sump 18 carries an annular pump assembly mounting and seal member 20.

On the mounting and seal member 20 is supported a motor driven plural pump assembly 22 for dishwashing apparatus of the present invention. As illustrated, the plural pump assembly 22 includes a rotatable spray arm 24 thereon to which fluid is supplied from the sump region 18 for distribution through the dishwashing chamber 14 during a cleaning cycle of dishwasher apparatus operation as established by a preprogrammable controller 26 including a plurality of actuable control buttons located on an upper panel of a downwardly opening front door 28 that closes an access opening 30 to the dishwashing chamber 14. In the illustrated arrangement, the door 28 is latched to its closed position by means including a handle 32 prior to advancing through a predetermined dishwashing cycle of operation including washing, rinsing, drying, and suitable drain cycles of operation.

A typical programmer for producing such a timer controlled cycle of operation is set forth in Patent No. 3,292,- 645 to Braden et al., issued Dec. 20, 1966. The Braden et al. patent further discloses a typical fluid distributing system including a rotatable spray arm like arm 24 in the illustrated arrangement. In order to maintain a substantial part of the volume of the cleaning chamber 14 for dish and article supporting racks of the type set forth in the Braden et al. patent, in accordance with certain principles of the present invention, the motor driven plural pump assembly 22 is characterized by being made up of a number of molded plastic parts having an outer dimensional configuration to reduce both the over-all vertical height of the motor pump assembly 22 as well as the dimensional extent to which the assembly 22 extends laterally within the sump region 18.

As is best seen in FIGURE 2, the pump assembly 22 includes a pump mounting plate 34 having a peripheral flange 36 thereon with a bottom surface 38 supportingly received by the mounting and seal member 20 for sealingly securing the motor driven pump assembly 22 to the depending sump forming portion of the bottom bulkhead 16. The pump mounting plate 34 includes a plurality of circumferentially located reinforced hubs 40 thereon in each of which is formed a stepped, re-entrant opening 42 receiving a threaded steel insert member 44 having a large diameter head 46 thereon interlocked in the reentrant opening 42 and a depending internally threaded distal end 48. The insert members 44 serve to interconnect a low profile drive motor unit 50 to the pump mounting plate 34.

More particularly, the drive motor unit 50 includes a sheet metal outer housing 52 having a plurality of air cooling openings 54 therein which is connected to and located in surrounding relationship with a stator block 56 having a coil 58 wound thereon. The housing 52 is closed at its lower end by a closure member 60 which has a plurality of radially extending arms 62 thereon, one of which is shown in FIGURE 1 that have the radially innermost end thereof integrally formed with a bearing housing 64 in which is located a sleeve bearing for rotatably supporting the lower end of a motor drive shaft 66 which is secured to a rotor 68. The motor 50 further includes an upper closure member 70 that has a plurality of circumferentially located radially extending arms 72 integrally formed with a bearing support 74 located centrally of member 70 and in which is located a sleeve bearing 76 for rotatably supporting the shaft 66 at the upper end of the motor 50. In the illustrated arrangement, the bearing hub 74 supports a seal cap 78 to protect the sleeve bearing 76 and above the seal cap 78 a seal slinger ring 80 is secured to the shaft for throwing fluid leakage from the sump region 18 outwardly of the space above cap 78 into a drain channel (not shown).

The shaft 66 extends above the slinger ring 80 through an opening 82 on a depending skirt 84 located centrally of the pump mounting plate 34 and arranged in over-lap ping surrounding relationship with the upper end of the bearing housing 74. The depending skirt 84 includes an internally formed seat 86 in which is supportingly located an annular seal assembly 88 to prevent fluid leakage from a drain pumping chamber 90 formed by a downwardly bulged portion 92 of the pump mounting plate 34.

The drain pumping chamber 90 is closed at its upper end by a lid 94 having an opening 96 therein surrounding the shaft 66 to define an annular inlet opening to the pumping chamber 90. As seen in FIGURE 6, within the pumping chamber 90 is located a drain impeller 98 having a plurality of upstanding curved pumping vanes 100 thereon. The impeller 98 further includes an upwardly directed sleeve 102 thereon that is suitably secured to the shaft 66 by means such as the key 104 on the shaft 66. The bulged portion 92 of the plate 34 defines a volute shaped inner surface 106 about the impeller 98 whereby upon rotation of the impeller 98 by the drive shaft 66 in the counterclockwise direction as seen in FIGURE 6, the impeller draws fluid from the inlet 96 into the pumping chamber 90 for discharge through a peripheral outlet 108 which is connected to a drain conduit 110 adapted to be connected to a household drain exteriorly of the dishwasher cabinet 12. Vent openings 111 in the impeller 98 prevent air pockets beneath the impeller and define a fluid path through which water passes during pump operation for cooling seal 88.

In the illustrated arrangement, which represents one working embodiment of the invention, the electric motor 50 is a one-third horsepower, -volt, 60-cycle reversible single phase induction motor operable at 3450 r.p.m. and the drain impeller 98 has eight equally spaced vanes each with a radius of inch located on a two-inch diameter base to produce a fluid discharge during the drain cycle of operation of four g.p.m. with a seven-foot discharge head of water into the drain conduit 110.

Above the drain pumping chamber 90 and in surrounding relationship to the upstanding vertically oriented drive shaft 66 is located a wash pump housing 112 of the assembly 22 that, as is best seen in FIGURES 2 and 3, includes a lower skirt 114 comprising a plurality of annular fluid strainers 116, 118, 120. Each of the strainers has a circumferential reinforcing hoop 122 with a plurality of depending ribs 124 formed therein to form a plurality of openings 125 in the lower skirt of the housing 112. The ribs 124 on strainer 116 contact an upper surface 126 on the pump mounting plate 34 whereby the ribs 122 strain fluid flowing across the surface 126 above or below an inverted saucer configured baffle member 128 located centrally within the wash pump housing 112. The baffle member 128 includes an outer peripheral edge 130 engaging the surface 126 which represents the lowest point in the sump 18 and further includes a plurality of circumferentially located ramps 132 thereon for directing fluid from the surface 126 upwardly within the pump housing 112.

The strainer 120 is connected to an upper tubular extension 134 of the housing 112 by a plurality of ribs 136 forming circumferentially located openings 138. Certain ones of the ribs extending upwardly across the outer surface of the extensions 134, as best seen in FIGURE 3, has outwardly projecting beads 140 which reinforce the extension 134 and serve as handle means during assembly of the housing 112 to a pump housing cover yet to be described and discussed.

The strainer rings 116, 118, 120 are of a progressively reduced diameter from the bottom of the skirt 114 to the top thereof for defining a stepped outer surface configuration on the skirt 114 that has been found especially suited to the dishwasher sump region 18 by including sufiicient surface area for enough windows or openings 125, 134 to allow free flow of fluid from the sump 18 into the pumps without occupying excessive lateral space in the sump.

The large open inlet flow area formed by the strainers 116, 118, 120 between the sump region of the dishwasher and the interior of the housing is divided by the baflie member 128 to communicate with a wash pump inlet chamber 142 and a drain pump inlet chamber 144. More particularly, the baffle 128 is supported on the housing 112 by a plurality of pairs of vertically directed flanges 146, 148 which are integrally connected to the skirt 114 of the housing 112 and to the inner surface of the housing extension 134 which is formed continuously around the upper end of the housing 112 and to an inwardly located depending support collar 152 that likewise is formed continuously around the circumference of the housing 112 interiorly thereof.

The collar 152 extends arcuately between each of the flanges 146, 148 as best seen in FIGURE 5 and the housing 112 includes a plurality of integral, arcuate segments 154 at circumferential points thereon, one of which extends between each of the flanges 146, 148 and is integrally formed with the baflle 128 to define a drain inlet passageway 156 from the sump 18 into the drain pump inlet chamber 144. Each of the inlet passageways has a width, best seen in FIGURE 3, as including the width of the arcuate segment 154, through which fluid is passed from radially aligned openings 125, 138 in the ring strainers of the housing skirt and the baffle member 128 includes a radially outwardly directed channel 158 thereon joined to each of the arcuate segments 154 and spaced apart flanges 146, 148 to separate the passageway 156 from the inlet chamber 142.

Each arcuate housing segment 154 includes an axial opening 160 through which an elongated screw member 162 extends into threaded engagement with the pump mounting plate 34 as best seen in FIGURE 2, for securing the pump housing 112 in place thereon. Between each of the openings 160 in the arcuate segments 154 is located a continuous circumferential support flange or ledge 164 on which is supported an impeller seal ring 166. At circumferentially located points above the ledge 164, the collar 152 has a plurality of locking lugs 168 directed radially inwardly above the outer upper peripheral surface on the ring 166, as best seen in FIGURES 2 and 5. It will be noted that the ring 166 is dimensioned to be freely movable both radially of the axis of rotation of the shaft 66 on the ledge 164 as well as axially between the ledge 164 and the under-surface of each of the lugs 168. A depending tab 169 on the ring 166 seats in a notched part of the ledge 164.

In accordance with certain principles of the present invention, the upper end of the drive shaft 66 is secured to a turbo type wash impeller assembly 170 that includes a hub member 172 with a radially outwardly and upwardly extending cover 174 and a depending sleeve segment 176 that includes inner slots 178 therein into which an interlocking integral key 180 on the end of the shaft 66 is seated to prevent relative rotation between the shaft and the impeller 170. To prevent axial movement of the assembly on the shaft 66, a retaining screw 182 is directed through the hub 172 into threaded engagement with the end of the shaft 66.

The impeller assembly 170 further includes a funnel shaped vane carrier 184 that has a depending skirt 186 thereon directed downwardly through a central opening 188 in the seal ring. The outer surface of the skirt 186 is engaged by a plurality of locating tabs 190 on the ring, as best seen in FIGURE 3, to locate the ring 166 with respect to the impeller vane carrier 184. It will be noted that the outer surface of the skirt 186 has a substantial length to locate the ring 166 thereon irrespective of assembly misalignment in both mounting the motor 50 on the pump plate 34 and any other tolerance differences between shafts, impeller, and the like that necessarily occur in mass production assembly operations. Furthermore, by virtue of the relationship of the ring 166 vis-a-vis the ledge 164 like radial tolerance differences in the assembly are readily compensated.

The skirt 186 defines an inlet throat 192 leading to a plurality of impeller passageways 194 formed between the vane carrier 184 and impeller hub 172 and by a plurality of equally spaced vanes 196 formed between the hub and carrier 184, as best seen in FIGURE 3. In the illustrated arrangement, each of the impeller vanes 196 has a leading edge 198 thereon extending from a point at the top of the inside surface of the skirt 186 at an angle of 45 in the direction of the axis of rotation of the shaft 66. Each of the vanes also include a trailing edge 200 extending from the upper edge of the outer peripheral surface of the carrier 184 at an angle like that of edge 198 as best seen in FIGURE 2.

Furthermore, in the illustrated embodiment, the impeller assembly 170 includes seven vanes thereon each of which is wrapped about the hub 172, as best seen in FIGURE 5. In one working embodiment, the maximum tip-to-tip blade diameter seen at D in FIGURE 7 is 2 inches and the height H of the hub member is 1% inches and its top width W is 2% inches. The envelope of the rotating vanes is shown in phantom outline in FIGURE 7 as having a total length of inch and an angle X of 45 from the horizontal along the length L and an angle Y of 37 from horizontal along the point where the vanes contact the undersurface of impeller cover 174. The above dimensions are cited merely as being illustrative of the configuration of a wash impeller found in a preferred mode of practicing the present invention. The impeller 70 is characterized functionally by an unusually good output head especially as compared to axial wash pumps used in dishwashers and it operates to draw fluid from inlet chamber 142 upon both clockwise and counterclockwise rotation of shaft 66.

The illustrated impeller assembly 170 when driven by the motor 50 at 3450 r.p.m. produces a wash fluid flow at the outlet of the impeller of 60 g.p.m. at a discharge head of 12 feet H O.

The turbo impeller assembly 170 described above produces this capacity during a washing cycle of operation when the reversible electric motor 50 is energized and conditioned to the impeller assembly 170 in a clockwise direction as viewed in FIGURE 5.

The fluid discharge from the impeller assembly 170 passes into a wash pumping chamber 202 bounded by the support collar 152 on its side and by the radially adjustable seated seal ring 166 to separate it from the inlet chamber 142. The discharge chamber 202 is closed at its top by a molded plastic diffuser cover 204, preferably of polypropylene, that includes a base section 206 having an outer surface shaped as a truncated cone. The skirt 208 of the base 206 includes a plurality of radially outwardly directed locking lugs 210 thereon which are located in interlocking relationship with bayonet openings 212 located at circumferentially spaced points in the inside surface of the upper edge of the extension 134 on the wash pump housing 112. Each of the bayonet openings 212 includes a vertical extent 214 and an inclined arcuate extent 216 therein so that when the lugs 210 are aligned with the extents 214 the cover 204 can be moved downwardly on the housing 112 until the bottom surface 218 thereon is seated on a continuously formed annular seat 220 forming the uppermost part of the support collar 152, as seen in FIGURES 2 and 3.

At this point, the cover 204 is located in its locked position with respect to the housing 112, as seen in FIGURE 2, by twisting the cover 204 so that the lugs 210 will be moved into a wedge interlocking relationship to the housing 112 in the extents 216 of the openings 212.

The diffuser cover also includes a vertically directed nose 222 with a shoulder 224 extending axially of the upper edge of the base 206. The nose 222 further includes a plurality of circumferentially located vertically directed spaced apart ribs 226 which join the shoulder 224 to an upper ring member 228 which includes an inwardly located internally threaded head 230. In the illustrated working embodiment, the nose 222 is inserted through the elongated arm 24 of the fluid distributing system within the dishwashing chamber 14. The spray arm 24 more particularly includes a downwardly directed inlet opening 232 that circumscribes the top axially directed shoulder 224 on the diffuser cover 204. The bar 24 is secured to the threaded head 230 of the vertically directed nose of the cover 204 by suitable fastening means such as illustrated screw element 234.

The diffuser cover 204 overlies and encloses a diffuser element 236 having a plurality of flow passageways 238 therethrough as defined by a conoidally shaped hub 240 which has the base thereof located at a point above the wash impeller 170 within the interior of the cover 204 and concentrically below the fluid distributing nose 222 on the cover 204. The plural passageways 238 through the diffuser 236 are formed by a plurality of equally spaced flow straightening vanes 242 each having a shape, as best seen in FIGURE 3, to receive circularly flowing fluid within the discharge chamber 202 for fluid fiow upwardly across the hub 240 of the diffuser into a generally axial direction for flow through the nose 222 into the spray bar 24.

Each of the vanes 242 more particularly include a pointed inlet edge 244 that depends from a bottom skirt 246 on the diffuser hub 240, as best seen in FIGURE 2. The depeding leading edge portions 24 each define a side passageway 248 into the diffuser flow passageways 238 between each of the vanes 242 and additionally fluid is free to flow axially upwardly from the discharge chamber 202 into the diffuser passageways 238.

The sharp leading edge 244 of each of the vanes angularly blends into two spaced apart side surfaces 250, 252 on each vane which are directed from an angular disposition on the hub 240 at the point that the leading edge depends from the skirt 246 into a straightened flow direction generally axially along the hub 240. The side surfaces 250, 252 are joined by an outer end surfaces 254 which has a curvature corresponding to that of the interior surface of the cover base 204 for seating the diffuser element 236 in place within the cover 204 so as to locate the leading edges 244 of the diffuser in a desired, unrestricted, fluid flow receiving relationship with the flow discharged from the trailing edges 200 of the wash impeller 170. In the illustrated working embodiment of the invention, the diffuser is formed as a single piece plastic molding preferably of polypropylene.

By virtue of the above-described relationship of the diffuser 236 vis-a-vis the wash impeller 170 and discharge chamber 202 there is an unusually high pressure fluid flow through the fluid distributing system into the cleaning chamber 14.

Another feature of the present invention is the provision of an axial impeller 256 of stainless steel having a sheet thickness of /32 inch. The impeller 256 is located within the inlet throat 192 of the wash impeller 170.

More particularly, the axial impeller 256 includes a mounting sleeve 258 thereon which press fits on the outer surface of the depending sleeve 176 of the hub member 170. Above the sleeve 258 are integrally formed a plurality of bent blades 260 each including a lower leading edge 262 and a raised trailing edge 264 between which the blade 260 is curved in accordance with the contour seen in FIGURE 11 at the angular reference points seen in FIGURE 9.

In the working embodiment under consideration, the axial impeller 256 has vanes thereon with the specific contour data listed below.

Angle, deg: X inch 0 .367 4 .346 8 .328 12 .308 16 .286 20 .263 24 .236 28 .204 32 .171 36 .132 40 .088 44 .043

The tip-to-tip diameter D of the impeller blades is 1.99 inches. The inside diameter ID. of the impeller is 71,- inch. The blade 260 curve through a distance H through the height of the axial impeller equal to 4 inch. Each of the blades 260 has the outer periphery 266 thereof in engagement with the inner surface of the depending skirt 186 on the impeller vane carrier so that fluid flow into the throat of the impeller must pass between thin radially extending openings 268 formed between the leading and trailing edges of adjacent ones of the axial impeller blades 260, as best seen in FIGURE 9.

The axial impeller in the illustrated embodiment includes seven equally spaced blades each with openings 268 between the leading and trailing edges in an axial direction approximately of an inch Wide and long whereby during rotation of the washing impeller 170 in its clockwise direction to draw fluid from the sump region 18 through the strainers 116, 118, into the inlet chamber 142 the edges of blades 260 will act on matter being drawn by the impeller through the throat 192 thereof to emulsify soft food particles and furthermore, to prevent hard particles of a predetermined size to enter impeller passageway 194 to damage the relatively soft plastic surfaces defining the passageways.

Another important feature of the above-described axial impeller 256 is to unload the wash pump impeller 170 during a drain cycle of operation to reduce noise level in the dishwashing apparatus and to reduce the load on motor 50. More particularly, by virtue of the blade formation described above, during a counterclockwise rotation of the shaft 66 on drain cycle of operation, the axial impeller will produce a pumping head that draws fluid from the turbo impeller passageways 194 and the discharge chamber 202 against the upward pumping action of Wash impeller 170 thereby to reduce physical impacting of the impeller on water located above the seal ring member 166. As a result, there is a reduced load imposed on the motor 50 and less noise transmitted by the pumping assembly 22 during the drain operation.

IT he operation of the above-described motor driven dish- Washer pump assembly has been in general terms, set forth above. For purposes of this specification, it is only necessary to inidicate by way of summary, that the controller 26 is operable to condition the motor 50 following a predetermined charging of the cleaning chamber 14 and sump 18 with water and detergent to drive the shaft 66 in a clockwise direction, as viewed in FIGURES 5 and 6, thereby causing the turbo wash impeller 170 to produce a differential pressure head causing the fluid in the chamber 14 to be drawn from the sump region 18 through the strainer tiers 116, 118, 120 thence into the inlet chamber 142. The fluid is separated from the inlet chamber 144 of the drain pump by the baffle member 128 and as it passes through the chamber 142, it is directed axially upwardly to the throat 192 thereby to be acted upon by the axial impeller 256 as discussed above.

The washing fluid is discharged by the impeller 170 in a circular fashion into the discharge chamber 202 where it is intercepted by the sharp leading edges 244 of the diffuser blades 242 thence to be directed through the diffuser passageways 238 from a circular flow path into a general axial flow path into the outlet nose 222 of the cover 204. The diffuser element 236 will convert the velocity head to a pressure head suitable for the rotatable spray bar 24 or an equivalent fluid distributing system within the dishwashing chamber 14 for passage against articles contained on suitable racks within the chamber 14.

During the above-described Washing cycle of operation, the drain impeller 98 will be driven in a like clockwise direction whereby the vanes 100 thereon merely free wheel in the voluted pumping chamber 90 without draining fluid from the sump.

During a drain cycle of operation, as generally set forth above, the controller 26 is operative to condition the motor 50 for counterclockwise rotation of the shaft 66 as viewed in FIGURES and 6. During this operation, the drain pump impeller 98 will have the vanes 100' thereon driven with respect to the voluted surface 106 of the pump ing chamber 90 thereby to produce a head differential causing fluid flow from the sump region 18 thence through arcuate segments of the strainer tiers aligned with passageway 156 formed by the pairs of spaced apart flanges 146, 148 thence to the channels 158 into the drain inlet chamber 144 beneath the saucer shaped baflle member 128. From the chamber 144 fluid flows through the inlet openings 96 to the drain pump chamber 90 for discharge through the outlet 106 into the drain conduit 110.

The drain cycle of operation is further characterized in that the Wash pump impeller 170, while configured to continue to direct fluid upwardly from chamber 142, is, by virtue of the pro-vision of the above-described axial impeller 256 in the inlet throat thereof, rendered inoperative and is drained of fluid by the axial impeller 256 so as to prevent impacting of the impeller against fluid in the discharge chamber 202 whereby during the drain cycle of operation the dishwashing apparatus runs at a reduced noise level and with its drive motor relatively lightly loaded.

In FIGURES 12 through 16 is illustrated a Wash impeller assembly that in another working embodiment of the invention is substituted for the turbo wash impeller assembly 170 described above. In the embodiment of FIGURES 12 through 16, the impeller includes an upper hub member 272 with an inverted truncated conically shaped head 274 having a maximum diameter D equal to 2 inches. The conical outer surface of the head 274 converges at an angle X of 45 from the horizontal to connect to a depending tubular extension 276 of the hub 272 that is adapted to be connected to the upper end of a drive shaft like the drive shaft 66 in the assembly shown in FIGURE 2 by means such as the connecting screw element 182.

In this embodiment of the invention, the turbo type wash impeller 270 has a vane carrier or funnel shaped bottom member 278 with a depending annular skirt 280 thereon defining an inlet throat 282 corresponding to throat 192 in the first embodiment. On the inner surface of the funnel shaped bottom member 278 are connected a plurality of equally spaced vanes 284 each of which has a leading edge 286 and a trailing edge 28 8 between which each of the vanes 284 is curved in a compound fashion along the length thereof.

Each of the vanes 284 prior to assembly of the vane carrying bottom member 278 to the upper hub member 272 includes a longitudinally directed tapered ridge 290 along the length thereof which serves as means to join the hub 272 with the carrier 278 when the longitudinally directed tapered ridge 290 is held against the underside of the conical head 274 of hub 272 and ultrasonic energy is applied to weld the separate parts.

In the embodiment of FIGURES 12 through 16 the vanes are seven in number and the impeller has the following configuration: diameter D representing the maximum outside diameter of vane carrier 2-78 equals 3 inches; diameter D the maximum tip-to-tip diameter of the vanes 284, equals 2 inches; D the distance between the upper part of the trailing edges 288 of diametrically opposed vanes, equals 2 inches; diameter D the inside diameter of the throat 282, is two inches; diameter D the OD. of the skirt 280, is 2% inches.

The inclination of the leading edge 286, represented by angle X equals 45; the inclination of the vane carrier 278 from the horizontal represented by angle X equals 48; the angle off the vertical of the trailing edge 288 represented by angle X equals 41.

In this embodiment, the height H of the member 278 equals 1% inches, and the height H of the skirt 28 equals approximately inch. The height H, of the ridge 290 equals inch.

Furthermore, the curvature of each of the blades 284 is approximated by the following schedule. The schedule includes inside radius dimensions at selected angular points on each of the blades in inches at horizontal plates A, C, E, G, located .1", .3, .5, .7", respectively from the top of the blades down. It is included merely as an illustrative example of the configuration of the vanes in the working embodiment of the turbo type wash impeller as seen in FIGURES 12 through 16.

IMPELLER BLADE CONTOUR SCHEDULE Angular position on vane This impeller 270 is formed of polyphenyleneoxide plastic material which is especially suited to the sonic welding connection of parts to form an impeller suitable for inclusion within the combination of FIGURE 2 and adapted to receive a member like 256 in the throat of the impeller 170 in the first embodiment to produce the dual function of reducing the size of soft food particles drawn from the sump region by impeller 170 and a further function of draining the turbo impeller during a drain cycle of operation thereby to unload the pump drive motor of the assembly.

While the embodiments of the present invention as herein disclosed constitute preferred forms, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. In dishwashing apparatus, means forming a cleaning chamber, means including a bottom wall in said cleaning chamber forming a sump for collecting cleaning fluid for distribution during a cleaning cycle of operation in the dishwashing apparatus, a pump mounting plate supported on said bottom wall, motor means on said mounting plate including a vertically upstanding drive shaft extending into said sump region, means for sealing said shaft against leakage from said sump region, a tubular wash pump housing surrounding said drive shaft in concentric relationship therewith including a skirt thereon formed by a plurality of annular fluid straining members, said wash pump housing including a radially inwardly directed support flange thereon, means including said skirt defining a wash pump inlet chamber interiorly of said wash pump housing and a wash pumping chamber, a Wash pump impeller secured to said drive shaft above said support flange Within said pumping chamber, said wash pump impeller including an annular, radially inwardly inclined surface thereon and a depending axial annular skirt thereon arranged generally concentrically of said support flange, said wash pump impeller including a plurality of vanes on said inclined impeller surface, each of said vanes having a leading edge and a trailing edge, said leading edge being located radially inwardly of the trailing edge thereon and at an angularly offset point on said wash pump impeller with respect to the trailing edge, a seal ring member centered on said depending annular skirt of said impeller extending radially outwardly thereof into a radially adjustable seated relationship with said support flange, said seal ring member being fixed against rotation with respect to said support flange and sealingly engaging said flange and annular skirt to prevent fluid bypassing from said wash pumping chamber into said inlet chamber, means including a diffuser member for directing fluid discharged from said wash impeller into said cleaning chamber, said depending skirt on said impeller defining an axial inlet throat to the pumping vanes thereon, a depending hub on said impeller located concentrically within said throat, an axial flow impeller located within said axial inlet throat including a sleeve portion thereon secured to said depending hub, said axial flow impeller including a plurality of radially outwardly directed blades skewed to the axis of rotation of said impeller, said axial flow impeller blades serving during a washing cycle of opertaion to emulsify soft food particles passing from said inlet chamber and to block passage of hard food particles of a predetermined size from passing into said wash pump impeller, said wash pump impeller being operative upon both directions of shaft rotation to draw fluid from said inlet chamber for discharge into said diffuser member, said axial flow impeller blades during a predetermined direction of shaft rotation serving to produce a pressure head opposite to that created by said wash pump impeller whereby fluid within said wash pumping chamber is discharged into said inlet chamber thereby reducing fluid noise emanating from said wash pump housing during the drain cycle of dishwashing apparatus operation while reducing the operational load on said motor means during the drain cycle.

2. In a dishwashing apparatus the combination of, means forming a cleaning chamber including a sump region therein with a bottom wall, a pump housing located within said sump region including a lower skirt supported on said bottom wall of said sump, said skirt forming an inlet chamber having a plurality of inlet openings through which washing and drain fluid can flow from said sump region interiorly of said pump housing, said skirt having a plurality of steps therein with a predetermined diameter at the bottom of said skirt and a predetermined reduced diameter at the top of said skirt for defining an outer surface area on said skirt with sufiicient inlet openings for free fluid flow from said sump region to interiorly of said pump housing and from said cleaning chamber downwardly into said sump, said pump housing including an upwardly directed tubular extension integrally joined to said upper step portion of said skirt to define the upper, outer peripheral extent of said pump housing and an interiorly located pumping chamber, means including a vertically directed shaft extending interiorly of said pumping chamber, an impeller member secured to said vertically directed shaft, said impeller member including pump vanes and a depending annular skirt thereon defining an axially directed impeller inlet communicating with said pump vanes, each of said vanes including a leading edge inclined downwardly from the axis of rotation of said vertically directed shaft, each of said blades wrapping about said impeller a predetermined angular extent and including a trailing edge also inclined downwardly with respect to the axis of rotation of said shaft, said tubular extension including a radially inwardly directed shoulder thereon, a ring seal member supported on said shoulder for free radial movement thereon, said ring including aligning means thereon engageable with said impeller skirt to center said ring seal member with respect to said impeller member along the length of said skirt, said ring serving to seal said inlet chamber from said pumping chamber and to compensate for radial and axial misalignment between said housing, said shaft and said impeller member;

3. In a dishwashing apparatus the combination of, means forming a cleaning chamber including a sump region therein with a bottom wall, a pump housing located within said sump region including a lower skirt supported on said bottom wall of said sump, said skirt having a plurality of vertically directed ribs thereon intersected by a plurality of integrally formed circumferentially directed reinforcing hoops, said vertically aligned ribs and circumferentially directed hoops forming a plurality of inlet openings in said pump housing skirt through which washing and drain fluid can flow from said sump region interiorly of said pump housing, said lower skirt having a plurality of steps therein with a predetermined diameter at the bottom of said skirt and a predetermined reduced diameter at the top of said skirt for defining an outer surface area on said skirt with sulficient inlet openings for free fluid flow from said sump region to interiorly of said pump housing and from said cleaning chamber downwardly into said sump, said pump housing including an upwardly directed tubular extension integrally joined to said upper step portion of said skirt to define the upper, outer peripheral extent of said pump housing and an interiorly located pumping chamber, a plurality of pairs of vertically directed flanges extending along the length of and inwardly of said tubular extension and being integrally formed therewith, each of said pairs of flanges depending downwardly from said tubular extension to form a drain inlet passageway radially inwardly of a predetermined arcuate extent of said skirt, an arcuate baflle member located within said skirt joined to said pair of flanges radially inwardly of said housing skirt, said baffle member including a plurality of channeled segments thereon each being integrally joined to said flanges for receiving fluid from said drain inlet passageways, said baflle member being located concentrically of said skirt and including a peripheral edge contacting the bottom wall of said sump to define a drain inlet chamber, said baflle member and said tubular extension along with said skirt defining a washing fluid inlet chamber, means including a vertically directed shaft extending upwardly through said baflle member and said washing inlet chamber interiorly of said pumping chamber, an impeller member secured to said vertically directed shaft, said impeller member including pumping vanes and a depending annular skirt thereon defining an axially directed impeller inlet communicating with said pumping vanes, each of said vanes including a leading edge inclined downwardly from the axis of rotation of said vertically directed shaft, each of said blades wrapping about said impeller a predetermined angular extent and including a trailing edge also inclined downwardly with respect to the axis of rotation of said shaft, said tubular extension including a radially inwardly directed shoulder thereon, a ring seal member supported on said shoulder for free radial movement thereon, said ring including aligning means thereon engageable with said impeller skirt to center said seal member with respect to said impeller member along the length of said skirt, said ring serving to seal said inlet chamber from said pumping chamber and to compensate for radial and axial misalignment between said housing, said shaft and said impeller member.

4. In a dishwashing apparatus the combination of, means forming a cleaning chamber including a sump region therein with a bottom wall, a pump housing located within said sump region including a lower shift supported on said bottom wall of said sump, said skirt having a plurality of vertically directed ribs thereon intersected by a plurality of integrally formed circumferentially directed reinforcing hoops, said vertically aligned ribs and circumferentially directed hoops forming a plurality of inlet openings in said pump housing skirt through which washing and drain fluid can flow from said sump region interiorly of said pump housing, said annular skirt having a plurality of steps therein with a predetermined diameter at the bottom of said skirt and a predetermined reduced diameter at the top of said skirt for defining an outer surface area on said skirt with sufficient inlet openings for free fluid flow from said sump region to interiorly of said pump housing and from said cleaning chamber downwardly into said sump, said pu-mp housing including an upwardly directed tubular extension integrally joined to said upper step portion of said skirt to define the upper, outer peripheral extent of said pump housing and an interiorly located pumping chamber, a plurality of pairs of vertically directed flanges extending along the length of and inwardly of said tubular extension and being integrally formed therewith, each of said pairs of flanges depending downwardly from said tubular extension to form a drain inlet passageway radially inwardly of a predetermined arcuate extent of said skirt, an arcuate baflie member located within said skirt joined to said pair of flanges radially inwardly of said housing skirt, said bafile member including a plurality of channeled segements thereon each being integrally joined to said flanges for receiving fluid from said drain inlet passageways, said bafiie member being located concentrically of said skirt and including a peripheral edge contacting the bottom wall of said sump to define a drain inlet chamber, said bafile member and said tubular extension along with said skirt defining a washing fluid inlet chamber, means including a vertically directed shaft extending upwardly through said baffle member and said washing inlet chamber interiorly of said pumping chamber, an impeller member secured to said vertically directed shaft, aid impeller member including pumping vanes and a depending annular skirt thereon defining an axially directed impeller inlet communicating with said pumping vanes, each of said vanes including a leading edge inclined downwardly from the axis of rotation of said vertically directed shaft, each of said blades wrapping about said impeller a predetermined angular extent and including a trailing edge also inclined downwardly with respect to the axis of rotation of said shaft, said tubular extension including a radially inwardly directed shoulder thereon, a ring seal member supported on said shoulder for free radial movement thereon, said ring including aligning means thereon engageable with said impeller skirt to center said ring seal member with respect to said impeller member along the length of said skirt, said ring serving to seal said inlet chamber from said pumping chamber and to compensate for radial and aixal misalignment between said housing, said shaft and said impeller member, a separate pump housing cover having a base thereon with an outer configuration of a generally truncated conical shape, said directed cover base including means for locking said cover to said housing, said cover base also including an axial extension upwardly from the small diameter end thereof including means thereon forming a plurality of radially outwardly facing openings for directing fluid from said pump cover into a fluid distributing system within said cleaning chamber, and a diffuser member located within said pump cover including a central hub having a conoidal shape and including a plurality of diffuser vanes thereon each having a leading edge inclined in a direction complementary to the inclination of said pump impeller vanes and a trailing edge inclined in an intersecting relationship with the leading edges, each of said diffuser vanes extending angularly around said central hub to direct fluid discharge from said impeller member from a circular motion into an axially vertical path, said diffuser vane leading edges depending below the lowest edge of said central hub to form radially directed openings into spaces between said diffuser vanes for reducing fluid flow restriction from said pumping chamber into said diffuser member.

References Cited UNITED STATES PATENTS 3,244,105 4/1966 La Flame 103-3 3,324,796 6/1967 La Flame 1033 3,265,311 8/1966 La Flame 103--3 3,364,860 1/1968 Schmitt et a1 103-3 HENRY F. RADUAZO, Primary Examiner.

U.S. CL. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,425 ,355 February 4 1969 Frank B. La Flame et al.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 7, line 57 "surfaces" should read surface Column 8, line 30, "blade" should read blades Column 13, line 23, "segements" should read segments Column 14, line 8, aixal" should read axial line ll, cancel "directed".

Signed and sealed this 14th day of April 1970.

(SEAL) Attest:

Edward .M. Fletcher, Jr. WILLIAM E. SCHUYLER, JR.

Attesting Officer Commissioner of Patents 

